This invention relates to surgical needles for tissue ablation, and more particularly, to surgical needles that are for ablation of uterine fibroids.
Approximately 20 to 40 percent of women have uterine fibroids (licomyomata). In the United States, fibroids result in approximately 175,000 hysterectomies and 20,000 myomectomies each year. Fibroids are well-defined, non-cancerous tumors that arise from the smooth muscle layer of the uterus. Approximately 25% of women suffer fibroid related symptoms, including menorrhagia (prolonged or heavy menstrual bleeding), pelvic pressure or pain, and reproductive dysfunction.
The most common treatments for fibroids include hysterectomy, abdominal myomectomy, laparoscopic myomectomy, hysteroscopic myomectomy, laparoscopy-directed needle mylosis, laparoscopy-directed needle cryomyolysis, high-intensity focused ultrasound ablation of fibroids, and uterine artery embolization. Hysterectomy is a major surgical procedure and carries with it the usual risk of surgery, such as hemorrhaging, lesions, complications, pain, and prolonged recovery. The majority of myomectomies are performed abdominally, wherein a surgeon creates an abdominal incision through which individual fibroids are removed. Abdominal myomectomy and laparoscopic myomectomy, like a hysterectomy, carries the usual risk of surgery.
Radio Frequency (RF) myolysis and thermal tissue ablation are two promising methods for treating fibroids. RF myolysis is a technique in which a RF probe is inserted into a fibroid or the surrounding tissue and then RF energy is applied to the tip of the probe. The tissue surrounding the tip is heated by the RF energy causing necrosis within the tissue. Thermal tissue ablation is a technique that is performed with a cryoablation probe. The cryoablation probe destroys the fibroid tissue by freezing it.
Current methods incorporating RF or cryoablation techniques require direct visualization of the needle tip or electronic imaging. Normally, under direct visualization techniques an endoscope is inserted into the uterus to position the needle. Direct visualization is often problematic because of the difficulties involved in simultaneously manipulating the endoscope and needle. Typically, when electronic imaging is used, the position of the needle is visualized with a hysteroscope or with an external abdominal ultrasound. Hysteroscopy allows direct visualization of the uterine cavity by inserting a small camera on the end of a long tube directly into the uterus through the vagina and cervix. Similar to an endoscope, a hysteroscope must be simultaneously manipulated with the needle, and thus is problematic. Monitoring the probe's position with current ultrasound techniques has a number of drawbacks. For example, a clinician using ultrasound imaging from an external source will have difficulty in distinguishing the uterine tissue from the surrounding organs and precisely locating the needle.
U.S. Pat. No. 5,979,453 to Savage et al. describes a myolysis needle that requires laparoscopic surgery. In laparoscopic surgery the needle must be placed through the uterine serosa into or near the fibroid. As a result, uterine adhesions often form that may cause chronic pain, infertility, and bowel obstruction. Additionally, during laparoscopic surgery the surgeon cannot visualize the tissue below the surface and must blindly place the needle, as a result placement may be sub-optimal.
U.S. Pat. No. 6,146,378 to Mikus et al. discloses a needle placement guide having an endoscope that is inserted into the uterus through the vagina. Using the endoscope, the surgeon positions the endoscopic guide in the correct orientation to the targeted fibroid. After positioning the guide, the endoscope is removed from within the guide and an ablation device is inserted into the guide for subsequent operation on the fibroid. The needle guide suffers from several disadvantages. There is the risk that the needle guide could shift during removal of the endoscope and insertion of the ablation device, resulting in sub-optimal performance. The needle cannot be relocated during the ablation procedure and the endoscope must be reinserted whenever it is necessary to reposition the needle guide. Reinserting and removing the endoscope and ablation device every time the needle must be repositioned increases the time and expense of the surgery.
U.S. Pat. No. 6,379,348 to Onik describes a mylolysis needle that is a combination of a cryosurgical and electrosurgical instrument for tissue ablation. The cryo/electro needle is not easily visualized when in use and requires the use of a dilator to create an access channel in the tissue area where the needle is to be inserted. Similar to laparscopic surgery, placement of the cryo/electro needle is done blindly and may not result in optimal performance.
Thus, a need exists to provide a medical needle system and method that can provide accurate and reliable targeting of fibroid tumors. It is also desirable to provide a needle that has a safety system that would shut-off electrical current to the needle if the uterine wall is punctured.